Flat metal roofs are often used in commercial buildings, such as merchandise stores and warehouses. Metal roofs often are covered with an insulating material such as polystyrene board, or urethane board. Polystyrene board, however, presents a fire hazard and requires the installation of an intermediate layer of fire retardant between the metal roof and the insulating polystyrene board. The fire retardant materials that are currently used include fiberboard, perlite board, or gypsum board. It is expensive to purchase and install such fire retardant materials.
Consequently, most commercial metal roofs today employ urethane insulating boards which do not require the intermediate layer of fire retardant. However, urethane production requires the use of chlorinated fluorocarbons which damage the environment, and contribute to the erosion of ozone in the atmosphere. Further, it appears that recently promulgated federal regulations will restrict or ban the use of chlorinated fluorocarbons in the future. Consequently, urethane roofing insulation could have to be processed using different methods that will result in lower fire retardant characteristics.
What is needed, therefore, is an inexpensive fire retardant composition that can be easily applied to building materials such as expanded polystyrene boards.